1. Field of the Invention
The present invention relates to a channel allocation technique of a third generation partnership project (3GPP), and more particularly to a method for allocating a physical channel of a mobile communication system that is capable of effectively allocating a physical channel of a RACH (Random Access Channel) and a CPCH (Common Packet Channel) having an up-link scrambling code, and a communication using the same.
2. Description of the Background Art
Generally, in the 3GPP system, the RACH and the CPCH, the up-link channels that a user terminal or a user equipment (UE) uses to transmit a data to a base station, uses 16 signatures and an OVSP (Orthogonal Variable Spreading Factor) code for allocating a physical channel.
That is, the terminal uses one of 16 signatures (Ap#s, #s=0, 1, 2, . . . , 15) to generate a preamble signature (Csig,s), generages a random access preamble code (Cpre,n,s) by using the generated preamble signature (Csig,s) and a specific physical RACH (PRACH) preamble scrambling code (Sr-pre,n) assigned per cell, carries the generated random access preamble code (Cpre,n,s) on an access preamble (AP) and transmits it to base station.
The random access preamble code (Cpre,n,s) is the sequence having a complex number value as shown in the below equation (1):                                           C                          pre              ,              n              ,              s                                ⁡                      (            k            )                          =                                            S                                                r                  -                  pre                                ,                n                                      ⁡                          (              k              )                                xc3x97                                    C                              sig                ,                s                                      ⁡                          (              k              )                                xc3x97                      ⅇ                          j              ⁡                              (                                                      π                    4                                    +                                                            π                      2                                        ⁢                    k                                                  )                                                                        (        1        )            
wherein, xe2x80x98kxe2x80x99 indicates a transmitted chip and is an integer of 0, 1, 2, . . . , 4096. Particularly, if xe2x80x98kxe2x80x99 is xe2x80x980xe2x80x99, it signifies the chip which is first transmitted for a corresponding time, xe2x80x98sxe2x80x99 is a signature number and an integer of 0, 1, 2, . . . ,15.
First, the physical channel allocation method of the RACH will now be explained with reference to the accompanying drawings.
FIG. 1 is a diagram showing a construction of a code tree for allocating a physical channel of the RACH in accordance with a conventional art.
As shown in the drawing, as a spreading factor (SF) is increased, an OVSP code is accordingly increased. For example, as for the 16 signatures (AP#0-AP#15), if the spreading factor (SF) is 16, each signature and the OVSF (Orthogonal Variable Spreading Factor) code is in a one-to-one ratio. The AP#0-AP#15 indicates the types of signature carried on the AP and transmitted by the terminal.
FIG. 2 is a diagram showing a construction of the OVSF code tree in accordance with the conventional art, which corresponds to the RACH physical channel allocation code tree of FIG. 1. That is, each of the tree of FIG. 1 is coded to the OVSF code (Cch,SF,K), having each value.
In the OVSF code (C ch,SF,k), the SF indicates a spreading factor, and xe2x80x98kxe2x80x99 indicates the order of the OVSF code. For example, in case of Cch2,1, its SF is 2 and xe2x80x98kxe2x80x99 is xe2x80x981xe2x80x99, indicating that it is the second code of the OVSF code.
Cch,SF,k has a code value allocated to each node in the OVSF code tree, of which xe2x80x98kxe2x80x99 also signifies the number of the node. In this case, a code value allocated to the node is obtained by the following equations (2) and (3):                               C                      ch            ,            1            ,            0                          =        1                            (        2        )                                          [                                                                      C                                      ch                    ,                    2                    ,                    0                                                                                                                        C                                      ch                    ,                    2                    ,                    1                                                                                ]                =                              [                                                                                C                                          ch                      ,                      1                      ,                      0                                                                                                            C                                          ch                      ,                      1                      ,                      0                                                                                                                                        C                                          ch                      ,                      1                      ,                      0                                                                                                            -                                          C                                              ch                        ,                        1                        ,                        0                                                                                                                  ]                    =                      [                                                            1                                                  1                                                                              1                                                                      -                    1                                                                        ]                                              (        3        )                                          [                                                                      C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                    0                                                                                                                        C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                    1                                                                                                                        C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                    2                                                                                                                        C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                    3                                                                                                      …                                                                                      C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                                                                  2                        ⁢                                                  (                                                      n                            +                            1                                                    )                                                                    -                      2                                                                                                                                            C                                      ch                    ,                                          2                      ⁢                                              (                                                  n                          +                          1                                                )                                                              ,                                                                  2                        ⁢                                                  (                                                      n                            +                            1                                                    )                                                                    -                      1                                                                                                    ]                =                  [                                                                      C                                      ch                    ,                                          2                      n                                        ,                    0                                                                                                C                                      ch                    ,                                          2                      n                                        ,                    0                                                                                                                        C                                      ch                    ,                                          2                      n                                        ,                    0                                                                                                -                                      C                                          ch                      ,                      1                      ,                      0                                                                                                                                            C                                      ch                    ,                                          2                      n                                        ,                    1                                                                                                C                                      ch                    ,                                          2                      n                                        ,                    1                                                                                                                        C                                      ch                    ,                                          2                      n                                        ,                    1                                                                                                -                                      C                                          ch                      ,                                              2                        n                                            ,                      1                                                                                                                                            …                  ⁢                                      xe2x80x83                                                                                                xe2x80x83                                                                                                      C                                      ch                    ,                                          2                      n                                        ,                                                                  2                        n                                            -                      1                                                                                                                    C                                      ch                    ,                                          2                      n                                        ,                                          2                                              n                        -                        1                                                                                                                                                                  C                                      ch                    ,                                          2                      n                                        ,                                                                  2                        n                                            -                      1                                                                                                                    -                                      C                                                                  ch                        ,                                                  2                          n                                                ,                                                  2                                                      n                            -                            1                                                                                              ⁢                                              xe2x80x83                                                                                                                          ]                                    (        4        )            
The OVSF code is a channelization code, which uses two types of codes for a data portion and a control portion of a message to be transmitted. The method for determining the two types of codes will now be explained.
FIG. 3 is a diagram of an OVSF code tree for explaining the method for allocating the OVSF code for a message of the PRACH (Physical Random Access Channel) in accordance with the conventional art.
For the data portion and the control portion of a message to be transmitted, as shown in FIG. 3, the OVSF code is allocated according to a particular rule (or a formula) along the tree at the right side from the node corresponding to a signature of the terminal itself.
For example, reference to the code tree of FIG. 1, if the SF of the signature is 16, the SF of the OVSF code for the data portion of the message is 32xcx9c256, the SF of the OVSF code for the control portion is 256 constantly. Accordingly, the PRACHs used by each terminal is identified by the OVSF code. In this respect, the every PRACH uses the same PRACH message part scrambling code.
FIG. 4 is a diagram showing a communication procedure between a terminal and a base station through the RACH physical channel as allocated in accordance with the conventional art.
When the terminal carries a specific signature on the AP and transmits it through the physical channel of the RACH allocated in the method of FIG. 1, the base station transmits an acquisition indicator (AI) through the AICH (Acquisition Indicator Channel).
Then, the terminal determines an OVSF code which is available to itself from the node corresponding to an acquired signature and transmits a message (MSG) to the base station by using the available OVSF code and a specific PRACH message part scrambling code which is allocated by one for one cell. The message (MSG) includes the data part and the control part.
FIG. 5 is a diagram showing a structure of an AICH in use for the 3GPP system in accordance with the conventional art.
One AICH includes 15 access slots (AS; AS#0, AS#1, . . . , AS#14), and has the length of about 20 ms. One AS has the length of 40 bit.
The AS includes a 32 bit (a0, a1, a2, . . . , a31) AI (Acquisition Indicator) part and a 8 bit (a32, a33, . . . , a39) part which is not transmitted.
The 32 bit AI is allocated to inform whether a signature previously transmitted by the terminal can be available to use. Thus, as the terminal interprets the bit of the AI part, it is judged whether a signature used in the access preamble can be available for use.
FIG. 6 illustrates a table indicating the number of the AS corresponding to the RACH sub-channel in used for the 3GPP system.
As shown in the drawing, the 3GPP system includes 12 RACH sub-channel for use, of which each sub-channel includes available access slots according to the current system frame number (SFN). The SFN is information given to the terminal by a P-CCPCH (Primary Common Control Physical Channel) and is used for various timings.
FIG. 7 illustrates a construction of a system for spreading the message part of the PRACH in the terminal in accordance with the conventional art.
The control part of the PRACH message has a real value and is diffused by a channelization code (Cc). The data part of the PRACH message has a real value and is diffused by a channelization code (Cd).
The two types of diffused signals are respectively multiplied by gain factors (Ad, Ac) to generate signals having a weight, which are outputted to an xe2x80x98I xe2x80x99 and a xe2x80x98Qxe2x80x99 branches.
Thereafter, the signal outputted to the xe2x80x98Ixe2x80x99 branch and the signal outputted to the xe2x80x98Qxe2x80x99 branch are multiplied by a complex factor (j) to generate complex signals, which are added to be converted to a complex signal stream (I+jQ).
The complex signal stream is a complex scrambling code, which is multiplied by the PRACH message part scrambling code (Sr-msg,n) so as to to be scrambled. The Sr-msgn and the PRACH preamble scrambling code Sr-msg,n used in the AP are in a one-to-one ratio.
Likewise in the RACH physical channel allocation method, the physical channel allocation method of the CPCH of the conventional art will now be described with reference to the accompanying drawings.
In the b 3GPP system of the conventional art, the terminal generates a PCPCH access preamble code Cc-acc,n,s, by using the access preamble signature (Csigs) produced by using one 16 signature AP#s (#s=0, 1, 2, . . . , 15) and a specific PRACH preamble scrambling code (Sc-acc,n) assigned per cell. Thereafter, the terminals carries the PCPCH access preamble code Cc-acc,n,s on the access preamble (AP) and transmits it to the base station.
The PCPCH (Physical Common Packet Channel) access preamble code Cc-acc,n,s is a sequence having a complex number value which is generated as shown in the below equation (5):                                           C                                          c                -                acc                            ,              n              ,              s                                ⁡                      (            k            )                          =                                            S                                                c                  -                  acc                                ,                n                                      ⁡                          (              k              )                                xc3x97                                    C                              sig                ,                s                                      ⁡                          (              k              )                                xc3x97                      ⅇ                          j              ⁢                              xe2x80x83                            ⁢                              (                                                      π                    4                                    +                                                            π                      2                                        ⁢                    k                                                  )                                                                        (        5        )            
wherein, xe2x80x9ckxe2x80x9d indicates a transmitted chip, and if the xe2x80x98kxe2x80x99 is xe2x80x980xe2x80x99, it indicates a chip which is the very first transmitted for a corresponding time, and xe2x80x98sxe2x80x99 is a signature number, which is an integer of 0, 1, 2, . . . , 15.
Also, the terminal generates a PCPCH CD preamble code (Cd-cd, n,s) by using the access preamble signature (Csig,s) generated by using one of the 16 signatures Ap#s (#s=0,1, 2, . . . , 15) and a specific PCPCH CD access preamble scrambling assigned per cell. Thereafter, the terminal carries the PCPCH CD preamble code on a CD preamble (referred to as xe2x80x98CDxe2x80x99, hereinafter) and then transmits it to the base station.
The PCPCH CD preamble code Cc-cd,n,s is a sequence having a complex number value generated in the below equation (6):                                           C                                          c                -                cd                            ,              n              ,              s                                ⁡                      (            k            )                          =                                            S                                                c                  -                  Cd                                ,                n                                      ⁡                          (              k              )                                xc3x97                                    C                              sig                ,                s                                      ⁡                          (              k              )                                ⁢                      xc3x97                          j              ⁢                              xe2x80x83                            ⁢                              (                                                      π                    4                                    +                                                            π                      2                                        ⁢                    k                                                  )                                                                        (        6        )            
wherein xe2x80x98kxe2x80x99 indicates a transmitted chip and is an integer of 0, 1, 2, . . . , 4096.
FIG. 8 is a diagram of the OVSF code tree for explaining the OVSF code allocation method for the message of the CPCH in accordance with the conventional art.
The OVSF code is a channelization code (OVSF Orthogonal Variable Spreading Factor) and requires two types of codes for the data part and the control part of a message to be transmitted. All of the terminals acquired for the CPCH transmission select an OVSF code from the same OVSF code set and use it.
At this time, the OVSF code for the data part and the control part of the message to be transmitted is allocated a required OVSF code according to a particular rule (or a formula).
The SF of the OVSF code for the data part and the control part of the message is 32xcx9c256. In this case, the PCPCHs used by each terminal is identified by the PCPCH message part scrambling code, and the every PCPCH uses the same type of OVSF codes.
The Cch,SF,k signifies the OVSF code, the SF signifies the spreading factor, xe2x80x98kxe2x80x99 signifies the order of a code among the OVSF codes having a corresponding SF. That is, Cch,SF,k are code values allocated to each node in the OVSF code tree. This is as shown in FIG. 2 and the values are defined as the equations (2), (3) and (4).
Accordingly, 16 PCPCH message part scrambling codes are allocated per cell and a single PCPCH access preamble scrambling code is allocated for the AP of the 16 PCPCH message part scrambling codes. Each PCPCH message part scrambling code and the signature AP#s are in a one-to-one ratio. That is, the 16 signatures AP#0xcx9cAP#15 and the 16 PCPCH message part scrambling codes are in a one-to-one ratio.
FIG. 9 illustrates a communication procedure between the terminal and the base station through the allocated CPCH physical channel in accordance with the conventional art.
When the terminal carries a specific signature on the AP and transmits it to the base station, the base station transmits an AI (Acquisition Indicator), that is, an acquisition response signal, through an AP-AICH (Access Preamblexe2x80x94AICH) to the terminal.
Then, the terminal transmits a collision detection (CD) to the base station. Upon receipt of the CD, the base station transmits the acquisition indicator (AI) through the CD-AICH to the terminal.
In this respect, the CD uses AP#0xcx9cAP#15, the same type of signatures used for the AP. The PCPCH CD access preamble scrambling code uses another part of the PCPCH access preamble scrambling code.
Then, the terminal transmits its message (MSG) by using the available OVSH code and the PCPCH message part scrambling code corresponding to the signature acquired through the AP-AICH. This message (MSG0 includes the data part and the control part.
The AP-AICH and the CD-AICH use the same one down link scrambling code (Sdl,n) and different types of channelization codes.
The AP-AICH and the CD-AICH have the same structure as shown in FIGS. 5 and 6.
FIG. 10 is a diagram of a system for spreading the message part of the PCPCH in the terminal in accordance with the conventional art.
The control part of the PCPCH message has a real value and is diffused by the channelization code (Cc). The two types of diffused signals are multiplied by the gain factors (Ad, Ac) to generate signals each having a weight, which are then outputted to the xe2x80x98Ixe2x80x99 and the xe2x80x98Qxe2x80x99 branches.
And then, the signal outputted to the xe2x80x98Ixe2x80x99 branch and a complex signal obtained as the signal outputted to the xe2x80x98Qxe2x80x99 branch is multiplied by a complex factor (j) are added and converted to a complex signal stream (I+jQ). As a complex scrambling code, the complex signal stream is multiplied by the PCPCH message part scrambling code (Sc-msg,n) to be scrambled. At this time, the Sc-msg,n is in a one-to-one ratio with the PCPCH preamble scrambling code Sc-msg,n used for the AP.
Accordingly, as for the physical channel allocation method for the RACH in accordance with the conventional art, since one PRACH preamble scrambling code is allocated to one cell and the RACH message part scrambling code for the message part to be transmitted are in the one-to-one ratio with the PRACH preamble scrambling code, the PRACH is not possibly re-used. In this respect, the PRACH message part scrambling code and the PRACH preamble scrambling code in the one-to-one ratio use different parts of the same long code.
In addition, as for the physical channel allocation method for the CPCH in accordance with the conventional art, since one PCPCH preamble scrambling code is allocated to one cell and the CPCH message part scrambling code for the message part to be transmitted are in the one-to-one ratio with the PCPCH preamble scrambling code, the PRACH is not possibly re-used. In this respect, the PCPCH message part scrambling code and the PCPCH preamble scrambling code in the one-to-one ratio use different parts of the same long code.
Therefore, an object of the present invention is to provide a physical channel allocation method of a mobile communication system that is capable of effectively allocating several signatures and a remaining up-link scrambling code per cell in a 3GPP system.
Another object of the present invention is to provide a physical channel allocation method of a mobile communication which is capable of effectively allocating a physical channel to allocate plural signatures and plural PRACH preamble scrambling codes per cell in a 3GPP system.
Still another object of the present invention is to provide an AICH structure suitable for allocating plural signatures and plural PRACH preamble scrambling codes per cell in a 3GPP system.
Yet another object of the present invention is to provide a physical channel allocation method of a mobile communication that is capable of effectively allocating a physical channel to allocate 16 signatures and plural PRACH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide an AICH structure suitable for allocating 16 signatures and plural PRACH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide a physical channel allocation method of a mobile communication that is capable of effectively allocating a physical channel to allocate plural signatures and plural PCPCH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide an AICH structure suitable for allocating plural signatures and plural PCPCH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide a physical channel allocation method of a mobile communication that is capable of effectively allocating a physical channel to allocate 16 signatures and plural PCPCH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide an AICH structure suitable for allocating 16 signatures and plural PCPCH preamble scrambling codes per cell in a 3GPP system.
Another object of the present invention is to provide a fresh physical random access procedure.
Another object of the present invention is to provide a physical channel allocation method of a mobile communication system that is capable of effectively allocating 16 signatures and more than 16 PCPCH access preambles (or PCPCH message part scrambling codes) per cell in consideration of a reuse factor.
Another object of the present invention is to provide a communication method of a mobile communication system by using a physical channel allocated by the plural signatures and plural PRACH preamble scrambling codes per cell.
According to a first feature of the present invention, in case that plural PRACH preamble scrambling codes (SC#m) for one cell in consideration of a reuse of the PRACH in a 3GPP system, a terminal transmits an access preamble (AP) by using one of 16 signatures (AP#s (s=0, . . . , 15) and a SC#m, one of PRACH preamble scrambling codes allocated to a corresponding cell to receive the PRACH.
According to a second feature of the present invention, when the transmitted AP is acquired by a base station according to the first feature, the terminal transmits its message by using a PRACH message part scrambling code MSC#m which is in a one-to-one ratio with the PRACH preamble scrambling ode SC#m used in the AP. In this case, the SC#m and the MSC#m are in a one-to-one ratio, and it would be more effective for the two codes to use a different part of the same code to each other.
According to a third feature of the present invention, in a terminal adopting the first feature, a signature available for the AP and the PRACH preamble scrambling code may be restricted by a higher layer for transmission of a corresponding RACH, for which an access service class (ASC) may be used.
According to a fourth feature of the present invention, for the AP transmitted from the terminal adopting the first through the third features, the base station informs whether the AP is allowable through plural AICHs (Acquisition Indicator Channel). In this case, the number of the AICHs is determined depending on the number of the PRACH preamble scrambling codes allocated to a corresponding cell. For example, different AICHs are responsible for acquisition of the AP using the different PRACH preamble scrambling codes SC#m. In this case, the SC#m, the SMC#m and the AICH#m are in a 1:1:1 ratio.
According to a fifth feature of the present invention, the AICHs according to the fourth feature commonly use a down-link scrambling code.
According to a sixth feature of the present invention, each AICH#m according to the fourth feature use different OVSF codes as a channelization code. That is, a channelization code Cch,S FM,Km are in a 1:1 ratio.
According to seventh feature of the present invention, the SC#m, the MSC#m, the AICH#m and Cch,S FM,Km in a 1:1:1:1 ratio.
According to an eighth feature of the present invention, if reuse of the PRACH is considered in the 3GPP system, in order for the terminal to be allocated with the PRACH to transmit a data to the base station, the terminal transmits an access preamble (AP) by using one of 16 signatures Ap#s (s=0, . . . ,15) and a SC#m, one of PRACH preamble scrambling codes allocated to a corresponding cell.
According to a ninth feature of the present invention, when the transmitted AP is acquired by the base station, the terminal transmits its message by using the PRACH message part scrambling code which is 1:1 ratio with the PRACH preamble scrambling code SC#m used in the access preamble.
According to a tenth feature, in order to transmit the RACH of the terminal adopting the eighth feature, a signature available in the access preamble and the PRACH preamble scrambling code are determined by an access service class (ASC) defined by a higher layer.
According to an eleventh feature of the present invention, the base station informs whether the access preamble transmitted from the terminal adopting the eighth to tenth features is allowable and general information on the current RACH through an AICH (Acquisition Indicator Channel) or a fresh physical channel (the fresh physical channel will be referred to as an xe2x80x98RRICH (RACH Reuse Indication Channel), hereinafter).
According to a twelfth feature of the present invention, for the access preamble transmitted from the terminal adopting the eighth to tenth features, the base station corrects the typical AICH structure and informs whether the access preamble is allowable through the corrected AICH.
According to a thirteenth feature of the present invention, the fresh physical channel (RRICH) having the eleventh feature utilizes the time during which bit transmission discontinues in one access slot (AS) of the typical AICH used for the RACH. Referring to the typical AICH used for the RACH, bits are transmitted for some time within one AS having the time length of {fraction (20/15)} msec and the transmission discontinues for the other remaining time. At this time, in order to minimize a complexity of hardware, the RRICH uses the same type of scrambling code and a channel identification code as those of the AICH. In this respect, however, a different type of codes may be used as necessary.
According to a fourteenth feature of the present invention, the information transmission unit of the fresh physical channel (RRICH) having the tenth to thirteenth features is the same as the access slot used by the typical AICH. That is, the transmitted information within one access slot having the length of {fraction (20/15)} msec is used as one information unit.
According to a fifteenth feature of the present invention, the information transmission unit of the fresh physical channel having the eleventh to thirteenth feature are the same as the 15 units of the access slot used by the typical AICH as necessary. That is, the fresh physical channel (RRICH) uses the transmitted information within the 15 access slots having the length of 20 msec as one information unit.
According to sixteenth feature of the present invention, in case that 16 signatures AP#s (s=0, . . . , 15) and xe2x80x98xxe2x80x99 number of PCPCH scrambling codes per cell are allocated in consideration of reuse of the PCPCH in the 3GPP system, xe2x80x98xxe2x80x99 number of PCPCH scrambling codes are classified by xe2x80x98yxe2x80x99 number of CPCH code channels. At this time, the PCPCH scrambling codes belonging to each CPCH code channel is used for a PCPCH message part scrambling code, of which two PCPCH scrambling codes are selected to be used for a PCPCH access preamble scrambling code and a PCPCH CD access preamble scrambling code.
For example, if xe2x80x98xxe2x80x99=64, y=4. That is, 4 CPCH code channels (code-channel#0xcx9ccode-channel#3) are generated, and code-channel#m has 16 PCPCH scrambling code.
According to a seventeenth feature of the present invention, in case that 16 signatures AP#s (s=0, 15) and xe2x80x98xxe2x80x99 number of PCPCH scrambling code per cell are allocated in consideration of reuse of the PCPCH in the 3GPP system, in order for the terminal to be allocated the PCPCH, the terminal transmits the AP by using one of 16 signatures AP#s and one of the PCPCH access preamble scrambling code APS#m (m=0,. . . . , 15) allocated to a corresponding cell.
According to an eighteenth feature of the present invention, in case that 16 signatures AP#s (s=0, . . . , 15) and xe2x80x98xxe2x80x99 number of PCPCH scrambling codes per cell are allocated in consideration of reuse of the PCPCH in the 3GPP system, in order for the terminal to be allocated the PCPCH, the terminal transmits the CD by using one of the 16 signatures AP#s and one of the PCPCH CD access preamble scrambling codes CD-APSC#m (m=0, . . . , M) allocated to the corresponding cell.
According to a nineteenth feature of the present invention, in order to the terminal adopting the sixteenth to the eighteenth features to transmit the CPCH, the signature and the PCPCH access preamble scrambling code (or PCPCH CD access preamble scrambling code) available for use in the AP (or the CD) are defined by the higher layer. In this case, an access service class (ASC) concept may be used for the higher layer.
According to a twentieth feature of the present invention, the AP and the CD transmitted according to the sixteenth to nineteenth features are acquired by the base station, the terminal transmits its message by using the PCPCH message part scrambling code MSC#n. At this time, the MSC#n is determined uniquely by the APSC#m and the AP#s used in the AP. That is, if the CPCH code channel to which the APSC#m belongs is the code-channel#m, the MSC#n is determined by the AP#s. The APSC#m and the MSC#n are codes belonging to the code-channel#m defined in the first feature of the present invention, and the correlation of xe2x80x98mxe2x80x99, xe2x80x98sxe2x80x99 and xe2x80x98nxe2x80x99 are previously defined.
According to twenty-first feature of the present invention, in response to the AP and the CD transmitted by the terminal having the above features, the base station informs whether they are allowable through several AP-AICHs and CD-AICHs. In this case, the number of the AICHs is determined depending on the number of the PCPCH scrambling codes allocated to the corresponding cell. For example, in case that there are four CPCH code channels (code-channel#0xcx9ccode-channel#3), four AP-AICHs and four CD-AICHs are required. That is, the AP-AICH#m is charged with the acquisition of the AP using the APSC#m and the CD-AICH#m is charged with the acquisition of the CD using the CD-APS#m. In this case, the APSC#m and the AP-AICH#m are in the 1:1 ratio and the CD-APSC#m and the CD-AICH#m are in the 1:1 ratio.
According to twenty-second feature of the present invention, the AP-AICHs and the CD-AICHs according to the twenty-first feature commonly use one down-link scrambling code. In this respect, all kinds of AICHs use different OVSF codes as a channelization code. That is, the AP-AICH#m and its channelization code CAPch,SFm,km are in a 1:1 ratio, and the CD-ALCH#m and its channelization code CD-AICH#m are in a 1:1 ratio. And, an arbitrary CAPch,SFm,km and an arbitrary CCDch,SFm,km are different to each other.
According to twenty-third feature of the present invention, the AP-AICHs having the twenty-first feature commonly use one down-link scrambling code, and the CD-AICHs also use commonly one down-link scrambling code. In this respect, however, the down-link scrambling code used by the AP-AICHs and the down-link scrambling code used by the CD-AICHs are to be different, and thus, there exist two down-link scrambling codes. Each AP-AICH use a different OVSF code as a channelization code, and each CD-AICH use a different OVSF code as a channelization code. That is, the AP-AICH#m and its channelization code CAPch,SFm,km are in a 1:1 ratio, and the CD-AICH#m and its channelization code CCDch,SFm,km are also in a 1:1 ratio. However, an arbitrary CAPch,SFm,km and an arbitrary CCDch,SFm,km may be the same or different to each other.
According to the twenty-fourth feature, in the 3GPP system, in case that 16 signatures AP#s (s=0, . . . , 15) and xe2x80x98xxe2x80x99 number of PCPCH scrambling codes per cell are allocated in order to reuse the PCPCH, the xe2x80x98xxe2x80x99 number of PCPCH scrambling codes are classified by xe2x80x98yxe2x80x99 number of code groups. The PCPCH scrambling codes belonging to each code group is used as a PCPCH message part scrambling code, of which two PCPCH message part scrambling codes are selected to be used as a PCPCH access preamble scrambling code and a PCPCH CD access preamble scrambling code. For example, if xe2x80x98xxe2x80x99=64, y=4. That is, four code groups are generated and each code group has 16 PCPCH scrambling codes.
According to the twenty-fifth feature, in case where reuse of the PCPCH is considered in the 3GPP system, in order for the terminal to be allocated the PCPCH, the terminal transmits an access preamble (AP) by using one of the 16 signatures AP#s (s=0, . . . , 15) and one of the PCPCH access preamble scrambling codes APSC#m (m=0, . . . , M) allocated to the corresponding cell.
According to the twenty-sixth feature of the present invention, in case where reuse of the PCPCH is considered in the 3GPP system, in order to the terminal to be allocated the PCPCH, the terminal transmits a collision detecting CD by using one of the 16 signatures AP#s and one of PCPCH CD access preamble scrambling codes CD-APSC#m (m=0, . . . , M) allocated to the corresponding cell.
According to the twenty-seventh feature of the present invention, in order for the terminal having the twenty-fifth and the twenty-sixth features to transmit the CPCH, the signature available for use in the AP (or the CD) and the PCPCH access preamble scrambling code (or the PCPCH CD access preamble scrambling code) are determined depending on the higher layer. In this case, a concept of an access service class (ASC) may be used.
According to the twenty-eighth feature, the AP and the CD transmitted according to the twenty-fifth and the twenty-sixth features are acquired by the base station, the terminal transmits its message by using the PCPCH message part scrambling code MSC#n. At this time, when a code group is determined by the APSC#m, the MSC#n is determined by the AP#s. The APSC#m and the MSC#n belong to the same code group defined in the first feature of the present invention.
According to a twenty-ninth feature of the present invention, the base station informs whether the AP and the CD transmitted by the terminal having the twenty-fifth and the twenty-sixth features is allowable and of the current general information through the conventional AICH and/or a fresh physical channel (the fresh physical channel will be referred to as a CRICH(CPCH Reuse Indicator Channel, hereinafter).
According to the thirtieth feature of the present invention, the base station informs whether the AP transmitted by the terminal having the twenty-fifth and the twenty-sixth features is allowable through a corrected AICH after the structure of the conventional AICH is corrected. This method is an alternative of the sixth feature of the present invention.
According to the thirty-first feature of the present invention, the fresh physical channel (CRICH) uses the time during which transmission of bits is stopped in an access slot (AS) of the conventional AICH used for the CPCH. As for the conventional AICH used for the CPCH, the bits are transmitted for some is time of one AS having the time length of {fraction (20/15)} msec and the transmission of bits are discontinued for the other remaining time. In this case, in order to minimize the complexity of the hardware, the CRICH uses the same type of scrambling code and channel identifying code as those of the AICH. In this respect, however, a different type of scrambling code and a channel identifying code may be used.
According to thirty-second feature of the present invention, the information transmission unit of the fresh physical channel (CRICH) according to the twenty-ninth and the thirty-first features are the same as one unit of the access slot used by the conventional AICH. For example, the information transmitted within one access slot having the time length of {fraction (20/15)} msec is used as one information unit.
According to a thirty-third feature of the present invention, the information transmission unit of the fresh physical channel (CRICH) according to the twenty-ninth and the thirty-first features is used in the same manner as the 15 units of the access slot used by the conventional AICH as required.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a communication method of a mobile communication system including: a step in which a terminal carries a preamble signature code (Csig,s) generated by using one of a plurality of signatures (AP#s) and a physical channel (PRACH) access preamble code (Cpre,n,s) of a first up-link generated by using one (SC#i) of xe2x80x98xxe2x80x99 number of physical channel (PRACH) preamble scrambling codes (SC#m) of the first up-link allowed to a corresponding cell, on an access preamble (AP), and transmits them to a base station through a channel (RACH) of the first up-link; a step in which the terminal receives an AI from the base station which decodes the signature included in the received AP and the type of the physical channel (PRACH) scrambling code of the first up-link and generates the AL informing whether the signature is available for use through a channel (AICH#m) of a first down-link; and a step in which the terminal transmits its message to the base station by using a channelization code that is determined by an acquired signature and the physical channel (PRACH) message part scrambling code (MSC#m) of the first up-link.
To achieve the above object, there is also provided a communication method of a mobile communication system including: a step in which a terminal carries a preamble signature code (Csig,s) generated by using one of a plurality of signatures (AP#s) and a PRACH access preamble code (Cpre,n,s) generated by using one (SC#i) of xe2x80x98xxe2x80x99 number of PRACH preamble scrambling codes (SC#m) allowed to a corresponding cell, on an access preamble (AP), and transmits them to a base station through RACH; a step in which the terminal receives an AI from the base station which decodes the signature included in the received AP and the type of the PRACH scrambling code and generates the AI informing whether the signature is available for use through a AICH#m; and a step in which the terminal transmits its message to the base station by using a channelization code that is determined by an acquired signature and the PRACH message part scrambling code (MSC#m).
The communication method of the mobile communication system includes an RRICH#m (Reuse RACH Indicator Channel) in consideration of a reuse factor of the RACH.
To achieve the above object, there is also provided a communication method of a mobile communication system including: a step in which a terminal carries a preamble signature code (Ca-acc,s) generated by using one of a plurality of signatures (AP#s) and a physical channel (PCPCH-CD) access preamble code (Cc-cd,n,s) of a second up-link generated by using one (CDSC#i) of xe2x80x98yxe2x80x99 number of physical channel (PCPCH-CD) preamble scrambling codes (CDSC#m) of the second up-link allowed to a corresponding cell, on an collision detecting preamble (CD), and transmits them to a base station through a channel (CPCH) of the first up-link; and a step in which the terminal receives an AI from a base station which generates the AI informing whether the CD for detecting a collision would meet a collision, through a channel (CD-AICH#m) of a second down-link.
To achieve the above object, there is also provided a communication method of a mobile communication system including: a step in which a terminal carries a preamble signature code (Csig,s) generated by using one of a plurality of signatures (AP#s) and a PCPCH access preamble code (Cpre,n,s) generated by using one (APSC#i) of xe2x80x98xxe2x80x99 number of PCPCH preamble scrambling codes (APSC#m) allowed to a corresponding cell, on an access preamble (AP), and transmits them to a base station through a CPCH; a step in which the terminal receives an AI from the base station which decodes the signature included in the received AP and the type of the PCPCH scrambling code and generates the AI informing whether the signature is available for use, through an AP-AICH#m; a step in which the terminal transmits its message to the base station by using a channelization code that is determined by the acquired signature and the physical channel (PRACH) message part scrambling code (MSC#m); a step in which the terminal carries a preamble signature code (Ca-acc,s) generated by using one of a plurality of signatures (AP#s) and a PCPCH-CD access preamble code (Cc-cd,n,s) generated by using one (CDSC#i) of xe2x80x98yxe2x80x99 number PCPCH-CD preamble scrambling codes (CDSC#m) allowed to a corresponding cell, on an collision detecting preamble (CD), and transmits them to a base station through the CPCH; a step in which the terminal receives an AI from a base station which generates the AI informing whether the CD for detecting a collision would meet a collision, through CD-AICH#m; and a step in which the terminal transmits its message to the base station by using the channelization code determined by the acquired signature and the PRACH message part scrambling code (MSC#m).
According to the communication method of a mobile communication system, the AP-AICH#m includes AP-CRICH#m, and the CD-AICH#m includes a CD-CRICM#m.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.